WO2014157881A1 - Resist underlayer composition and method for forming pattern using same - Google Patents

Abstract

Disclosed are a resist underlayer composition with remarkable thermal stability and etching resistance and excellent gap fill properties, and a method for forming a pattern using the same. The resist underlayer composition comprises: an aromatic ring-containing polymer comprising a repeating unit represented by chemical formula 1 in the specification; a compound represented by chemical formula 4 in the specification; and an organic solvent. In chemical formula 1 in the specification, R₁ is a C₅-C₂₀ monocyclic or polycyclic aromatic hydrocarbon group, R₂ and R₃ are independently a C₄-C₁₄ monocyclic or polycyclic aromatic hydrocarbon group, a is an integer of 1-3, and b is an integer of 0-2. In chemical formula 4 in the specification, n is an integer of 1-250.

Description

Resist Underlayer Film Composition and Pattern Forming Method Using the Same

The present invention relates to a resist underlayer film composition and a pattern forming method using the same, and more particularly, to a resist underlayer film having excellent thermal stability and etching resistance as well as excellent flatness and void suppression properties during gap fill. It relates to a composition and a pattern forming method using the same.

In recent years, with the high integration and high speed of large scale integrated circuits (LSI), semiconductor patterns have become more fine, and in lithography using light exposure, which is currently used as a general-purpose technology, it is derived from the wavelength of a light source. Is approaching the limit of inherent resolution. As a light source for lithography used to form a resist pattern, g-line (436 nm) and i-line (365 nm) using a mercury lamp have been widely used. Recently, in order to refine the pattern, KrF excimer laser ( A lithography process is performed using short wavelength light sources such as an excimer laser (248 nm) and an ArF excimer laser (193 nm).

In addition, with the miniaturization and integration of semiconductor devices, as the size of the pattern becomes smaller, the thickness of the photoresist film and the pattern is gradually thinner in order to prevent the photoresist pattern from falling down. However, since it is difficult to etch (etch) the layer to be etched using the thinned photoresist pattern, an inorganic or organic layer having strong etching resistance is introduced between the photoresist and the layer to be etched, and the layer is formed as an underlayer or hard layer. It is called a mask, and the process of etching and patterning an underlayer film using a photoresist pattern, and also etching a to-be-etched layer using the pattern of an underlayer film is called an underlayer film process. The inorganic underlayer film used in the underlayer film process is made of silicon nitride, silicon oxynitride, polysilicon, titanium nitride, amorphous carbon, and the like, and is typically a chemical vapor deposition (CVD) method. Is formed. Although the underlayer film produced by the chemical vapor deposition method is excellent in etching selectivity and etching resistance, there are some problems such as particle problems and initial equipment investment costs. As a method for solving this problem, instead of the deposition type underlayer film, an organic underlayer film capable of spin coating has been studied.

The multilayer film resist including the organic underlayer film usually has a two-layer film structure (two-layer resist method) or a three-layer film structure (three-layer resist method). In the case of a resist having a two-layer film structure, the upper layer film is a photoresist film capable of realizing a pattern, and the resist lower layer film is a hydrocarbon compound capable of an etching process by oxygen gas. The resist underlayer film should have a high etching resistance because it should act as a hard mask when etching the substrate below it, and hydrocarbons containing no silicon atoms for oxygen gas etching. It needs to be composed only. In addition, the wafer on which the resist underlayer film is coated may be not only a wafer having a flat surface, but also a wafer on which a semiconductor pattern is formed in some cases. Since the line width and height of the semiconductor pattern formed as described above are about several tens to hundreds of nanometers, the resist underlayer material coated on the pattern requires a gap fill property so as to be effectively filled between the pattern having a high step and the pattern. do. In addition to such etching resistance and gap fill characteristics, the resist underlayer film also has a function of an antireflection film of the light source in order to prevent standing wave control and pattern collapse of the upper resist film when KrF and ArF light sources are used. There is a need. Specifically, it is necessary to suppress the reflectance from the lower layer film to the resist upper layer film to 1% or less.

In the case of a resist having a three-layer film structure, an inorganic hard mask intermediate layer film (second lower layer film made of inorganic material) is further formed between the upper layer film (photoresist film) and the resist underlayer film (first lower layer film made of a hydrocarbon compound). do. As the second underlayer film, a silicon oxide film (silicon oxide film), a silicon nitride film (silicon nitride film), a silicon oxynitride film (silicon oxynitride film, a SiON film), or the like formed by chemical vapor deposition at a high temperature may be used. Preferably, a SiON film having a high effect as an antireflection film can be used. The film thickness of the second underlayer film is 5 to 200 nm, preferably 10 to 100 nm. In order to form a second underlayer film (particularly, a SiON film) on the resist underlayer film (first underlayer film), the temperature of the substrate must be raised to 240 to 500 ° C. Thus, the resist underlayer film (first underlayer film) used is It should have thermal stability at 240 degrees to 500 ° C. If the resist underlayer film does not have thermal stability at a high temperature (for example, 400 ° C. or more), there is a fear that the resist underlayer film is decomposed to contaminate the inside of the equipment when the inorganic hard mask interlayer film (second underlayer film) is formed.

Accordingly, an object of the present invention is to provide a resist underlayer film composition capable of forming a resist underlayer film excellent in thermal stability and etching resistance at high temperature (for example, 400 ° C. or higher) and a pattern forming method using the same.

Another object of the present invention is to provide a resist underlayer film composition having excellent gap fill characteristics and a pattern forming method using the same.

In order to achieve the above object, the present invention provides a resist underlayer film composition comprising an aromatic ring-containing polymer comprising a repeating unit represented by the following formula (1), a compound represented by the following formula (4), and an organic solvent.

 [Formula 1]

In Formula 1, R ₁ is a monocyclic or polycyclic aromatic hydrocarbon group having 5 to 20 carbon atoms, R ₂ and R ₃ are each independently a monocyclic or polycyclic aromatic hydrocarbon group having 4 to 14 carbon atoms, a is an integer from 1 to 3 and b is an integer from 0 to 2;

[Formula 4]

In Chemical Formula 4, n is an integer of 1 to 250, preferably an integer of 2 to 150, more preferably an integer of 10 to 100.

In addition, the present invention, forming a resist underlayer film on the substrate to be etched using the resist underlayer film composition; Forming a photoresist layer on the resist underlayer film; Generating a pattern of radiation-exposed regions of the photoresist layer by exposing the photoresist layer to radiation in a predetermined pattern; Selectively removing the photoresist layer and the resist underlayer film along the pattern to expose the substrate in the form of the pattern; And etching the exposed portion of the substrate.

The resist underlayer film formed according to the present invention is excellent in high temperature (eg, 400 ° C. or higher) thermal stability required when forming a hard mask, and when coated on top of a pattern having a height step, void gap characteristics are excellent. ), Suppression of formation, excellent leveling of film quality, and can have performance as an organic antireflection film during film formation. In addition, the resist underlayer film formed according to the present invention is excellent in etching resistance, and serves as a protective film (hard mask) for forming a pattern of a predetermined pattern during the dry etching process, and the faster or slower the etching speed of the resist film, The loss can be minimized and the etching amount (etching amount) of the lower layer can be increased. The excellent gap fill characteristics of the lower layer and the increase in the etching amount can increase the depth of the etching pattern, thereby making it easier to widen the interlayer gap between the upper layer and the lower layer when forming a semiconductor chip. have. Therefore, it is useful for semiconductor production processes.

1 and 2 show FE-SEM cross-sectional photographs of the resist underlayer film formed in Comparative Example 4-1 and the resist underlayer film formed in Example 4-10, respectively.

Hereinafter, the present invention will be described in detail.

The resist underlayer film composition according to the present invention is for forming an underlayer film on a substrate such as a silicon wafer by spin coating (spin coating, spin on carbon) or the like, and an aromatic ring including a repeating unit represented by the following Chemical Formula 1 It contains a polymer, a compound represented by following formula (4), and an organic solvent.

Formula 1

In Formula 1, R ₁ is a monocyclic or polycyclic aromatic hydrocarbon group having 5 to 20 carbon atoms, for example, R ₁ ring is a benzene ring, naphthalene ring, biphenyl ring, anthracene ring, phenanthrene Aromatic rings such as a ring, a triphenyl ring, a pyrene ring, a binaphthalene ring, and the like, and R ₂ and R ₃ are each independently a monocyclic or polycyclic aromatic hydrocarbon group having 4 to 14 carbon atoms, for example, The R ₂ and R ₃ rings each independently represent an aromatic ring such as a benzene ring, a naphthalene ring, an anthracene ring and the like. a is the number of hydroxy groups (-OH) substituted with R ₁ , an integer of 1 to 3, and b is an integer of 0 to 2. In addition, as needed, R ₁ , R ₂ and R ₃ may be further substituted with a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, a lower alkyl group having 1 to 6 carbon atoms, and the like.

The aromatic ring-containing polymer including the repeating unit represented by Chemical Formula 1 has no ethylene group (-CH _2- ) in the backbone of the polymer, and representative examples of the aromatic ring-containing polymer include the following Chemical Formulas 1a to The polymer containing the repeating unit represented by 1m can be illustrated.

[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

[Formula 1e]

[Formula 1f]

[Formula 1g]

[Formula 1h]

Formula 1i]

[Formula 1j]

[Formula 1k]

[Formula 1l]

[Formula 1m]

The aromatic ring-containing polymer, for example, as shown in Scheme 1 below, a monomer (cyclic compound containing a ketone group) represented by the formula (Formula 2) and a monomer represented by the formula (Formula 3) The (phenol derivative compound) can be produced by reacting (heating) in a solvent in the presence of an acid catalyst, and can be prepared according to the following preparation example.

Scheme 1

In Scheme 1, R ₁ , R ₂ and R ₃ , a and b are the same as defined in Formula 1.

Representative examples of the monomer represented by the formula (Formula 2),

And the like, and as an example of the monomer represented by Formula 3 (Formula 3),

Etc. can be illustrated.

In the preparation of the aromatic ring-containing polymer (Scheme 1), the content of the monomer represented by Formula 3 is 0.5 to 4 times (molar ratio), preferably 1 to 2 times, relative to the monomer represented by Formula 2, More preferably, it is 1 to 1.2 times. When the content of the monomer represented by Formula 3 exceeds 4 times (molar ratio) with respect to the monomer represented by Formula 2, the ratio of the phenol derivative compound (monomer represented by Formula 3) containing a hydroxyl group is high. If the compound may not be formed, and if it is less than 0.5 times (molar ratio), the ratio of the cyclic compound (monomer represented by Formula 2) containing the ketone group is relatively high, so that the yield of the polymer compound may be lowered. In addition, the aromatic ring-containing polymer including the repeating unit represented by the formula (1) may include a small amount of other repeating units within the scope of not impairing the object of the present invention.

As an acid catalyst used in the production of the aromatic ring-containing polymer, conventional acid catalysts such as sulfuric acid, hydrochloric acid, phosphoric acid, paratoluenesulphonic acid, methyl sulfonic acid, oxalic acid, acetic acid, and mixtures thereof Can be illustrated. The content of the acid catalyst is 5 to 100 mol parts, preferably 10 to 50 mol parts, and more preferably 10 to 20 mol parts with respect to 100 mol parts of the monomer represented by the formula (2). When the content of the acid catalyst is less than 5 mol parts with respect to 100 mol parts of the monomer represented by Formula 2, the reaction progress rate may be slow, and a large amount of reaction time may be required. At the end of the reaction, there is a concern that the use of excess sodium hydroxide in the neutralization process and the neutralization time due to this may take a long time. As a solvent used in the preparation of the aromatic ring-containing polymer, a conventional organic solvent capable of dissolving the monomers can be used without particular limitation, and preferably toluene, xylene, 1,2,3,4-tetra Organic solvents such as hydronaphthalene (1,2,3,4-tetra hydronaphthalene (THN)) can be used.

In addition, when preparing the aromatic ring-containing polymer, a mercaptothiol derivative may be further used together with the acid catalyst. The mercaptothiol derivative is a catalyst that lowers the activation energy of the reaction, thereby allowing the polymerization reaction to proceed even if a steric hindrance between the cyclic compound containing the ketone group and the phenol derivative compound occurs in the condensation reaction. The mercaptothiol derivatives include 2-mercaptoethanol, 2-mercaptopropanol, 2-mercaptopropanol, 3-mercaptopropanol, and 4-mercaptobutanol. , Mixtures thereof and the like can be exemplified. When using the mercaptothiol derivative, the content of the mercaptothiol derivative is 50 to 100 moles, preferably 60 to 90 moles with respect to 100 moles of the acid catalyst. When the content of the mercaptothiol derivative is less than 50 mol parts with respect to 100 mol parts of the acid catalyst, there is a fear that the synthesis of the polymer may not be performed smoothly, and even if it exceeds 100 mol parts, there is no particular advantage in terms of reaction rate or yield. .

The weight average molecular weight (Mw) of the aromatic ring-containing polymer including the repeating unit represented by Formula 1 is, for example, 200 to 50,000, preferably 400 to 10,000, more preferably 500 to 8,000. If the weight average molecular weight of the aromatic ring-containing polymer is less than 200, the formation of a resist underlayer film may be difficult. If the weight average molecular weight is more than 50,000, the polymer may not be dissolved in a solvent and the resist underlayer film composition may not be prepared.

Formula 4

In Formula 4, n is an integer of 1 to 250, preferably an integer of 2 to 150, more preferably an integer of 10 to 100. The weight average molecular weight (Mw) of the compound represented by Formula 4 is, for example, 200 to 30,000, preferably 300 to 20,000, more preferably 500 to 10,000. If the weight average molecular weight of the compound represented by the formula (4) is too small, the ratio of the monomolecular compound in the resist is high, the coating surface is poor during coating, or the amount of outgas generated during the high temperature heating process may increase, the weight If the average molecular weight is too large, the polymer is insoluble in the solvent to be used, there is a fear that a step occurs when coating using the composition.

The compound represented by Formula 4 is an additive for improving the gap fill property when the resist underlayer film composition according to the present invention is spin coated on a substrate such as a silicon wafer. It acts as a leveling agent. The compound (additive) represented by the formula (4) may be a monomolecular compound or a high molecular compound, preferably a high molecular compound. As the compound represented by the formula (4), a commercially available noblock-based polymer (for example, Meiwa Corporation (MEIWA) MER-series, etc.) may be exemplified.

As the organic solvent used in the present invention, an aromatic ring-containing polymer including a repeating unit represented by the formula (1), a conventional organic solvent for an underlayer film having solubility to the polymer represented by the formula (4) may be used. For example, propylene glycol monomethylether acetate (PGMEA), propyleneglycol monomethyl ether (PGME), cyclohexanone (CH), ethyl lactate (EL), gamma Butyrolactone (gamma-butyrolactone (GBL)), mixtures thereof and the like can be used.

In the resist underlayer film composition of the present invention, the content of the aromatic ring-containing polymer including the repeating unit represented by Chemical Formula 1 is 1 to 25% by weight, preferably 3 to 20% by weight, more preferably 4 to 16%. Weight percent. If the content of the aromatic ring-containing polymer including the repeating unit represented by the formula (1) is less than 1% by weight, there is a fear that the lower layer film may not be formed, and if it exceeds 25% by weight, the resist film quality may be poor during coating. . In addition, the content (usage) of the compound represented by Formula 4 is 30 to 150 parts by weight, preferably 50 to 140 parts by weight, based on 100 parts by weight of the aromatic ring-containing polymer including the repeating unit represented by Formula 1. More preferably, it is 70-110 weight part. If the amount of the compound represented by the formula (4) is less than 30 parts by weight with respect to 100 parts by weight of the aromatic ring-containing polymer including the repeating unit represented by the formula (1), the resist underlayer of the present invention is on the pattern having a high step When coating the film composition, gap gap characteristics are poor, voids may be formed inside the pattern, or there may be a large step, and if it exceeds 150 parts by weight, the high temperature thermal stability of the resist underlayer film may be deteriorated. At the time of an etching process, etching resistance may fall. The content of the organic solvent is the remainder except for the solid content of the aromatic ring-containing polymer including the repeating unit represented by the formula (1), the compound represented by the formula (4) and the like.

Moreover, the resist underlayer film composition which concerns on this invention can further contain additives, such as a crosslinking agent, surfactant, an acid generator, as needed. The crosslinking agent is to induce a crosslinking reaction to further cure the underlayer film, and may use a conventional crosslinking agent such as melamine type and epoxy type. For example, as a commercially available crosslinking agent, MX-270, MX-280, which is a chemical crosslinking agent, may be used. , MX-390 and 2-{[4- (2-oxiranylmethoxy) phenoxy] methyl} oxirane (2-{[4- (2-oxiranylmethoxy) phenoxy] methyl} oxirane) and the like can be used. When using the crosslinking agent, the content of the crosslinking agent is 1 to 20 parts by weight, preferably 3 to 15 parts by weight based on 100 parts by weight of the aromatic ring-containing polymer including the repeating unit represented by Chemical Formula 1. When the content of the crosslinking agent is less than 1 part by weight based on 100 parts by weight of the aromatic ring-containing polymer, a sufficient crosslinking rate may not be obtained due to the addition of the crosslinking agent. When the content of the crosslinking agent is more than 20 parts by weight, the stability of the resist may be lowered.

The acid generator may be added to lower the temperature of the crosslinking reaction of the polymer and improve the crosslinking rate. As the acid generator, conventional photoacid generators and thermal acid generators may be used, and in some cases, an acid may be used. Preferably, a thermal acid generator having excellent efficiency as a catalyst at a higher temperature than the photoacid generator can be used. For example, a thermal acid generator such as TAG-series manufactured by King Industries can be used. When using the acid generator, the amount of the acid generator is 5 parts by weight or less, preferably 1 to 4 parts by weight based on 100 parts by weight of the aromatic ring-containing polymer including the repeating unit represented by the formula (1). . When the usage-amount of the said acid generator exceeds 5 weight part with respect to 100 weight part of said aromatic ring containing polymers, there exists a possibility that the stability of a resist may fall.

The surfactant may be used to improve coating defects caused by an increase in solid content when forming a resist underlayer film. For example, a sulfinol-based, commercially available surfactant, and an F-series (DIC) F-410, F-444, F-477, R-08, R-30, etc.) can be used. When using the surfactant, the content of the surfactant is 0.1 to 1 parts by weight, preferably 0.2 to 0.8 parts by weight based on 100 parts by weight of the total resist underlayer film composition. When content of the said surfactant exceeds 1 weight part with respect to 100 weight part of whole resist underlayer film compositions, there exists a possibility that a resist film quality may become bad. The resist underlayer film composition according to the present invention can be prepared by blending the above components in a conventional manner.

In addition, the present invention provides a pattern forming method using the resist underlayer film composition. Specifically, the pattern forming method includes the steps of: (a) forming a resist underlayer film on the substrate to be etched (for example, a silicon wafer on which an aluminum layer is formed) using the resist underlayer film composition according to the present invention; (b) forming a photoresist layer on the resist underlayer film; (c) exposing the photoresist layer to radiation in a predetermined pattern to produce a pattern of radiation exposed regions in the photoresist layer; (d) selectively removing the photoresist layer and the resist underlayer film along the pattern to expose the substrate in the form of the pattern; And (e) etching the exposed portion of the substrate. Further, if necessary, before the step (b), a conventional silicon-containing resist underlayer (inorganic underlayer) and / or a bottom anti-refractive coating (BARC) is further formed on the resist underlayer. You can also

Forming the resist underlayer film, the resist underlayer film composition according to the invention is applied to the upper substrate (spin coating, etc.) to a thickness of 40 to 600 nm, and at a temperature of 240 to 400 ℃, preferably 350 to 400 ℃ , For example, by heating for 50 to 180 seconds, and the thickness of the resist underlayer film thus formed is approximately 40 to 550 nm. Here, if the heating temperature is less than 240 ℃, the crosslinking rate is lowered, there is a risk that the etching resistance of the resist is lowered, if it exceeds 400 ℃ there is a fear that the polymer is pyrolyzed to contaminate the inside of the equipment. In addition, the patterning of the photoresist film may be performed by a development using a conventional alkaline aqueous solution such as TMAH developer, and the removal of the underlayer film may be performed by dry etching using a CHF ₃ / CF ₄ mixed gas or the like. The substrate may be etched by plasma etching using Cl ₂ or HBr gas. Here, the thickness of the resist underlayer film, the heating temperature and time, the etching method and the like are not limited to the above contents, and may be variously changed according to process conditions.

Since the resist underlayer film formed in accordance with the present invention contains an aromatic ring in the polymer, it is possible to minimize light reflection, to have the performance as an organic antireflection film, and to have excellent gap fill characteristics for a pattern having a step. A flat surface can be realized. In addition, the resist underlayer film formed according to the present invention serves as a protective film (hard mask) for forming a predetermined pattern during the dry etching process, and the loss of the mask can be minimized as the etching speed of the resist film is increased or decreased. , The etching amount (etching amount) of the lower layer can be increased. Such an increase in the etching amount of the lower layer quality can make the depth of the etching pattern deeper, thereby making it easier to widen the interlayer gap between the upper layer and the lower layer when forming a semiconductor chip. Therefore, it is useful for semiconductor production processes.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are intended to illustrate the invention, and the invention is not limited by the following examples.

Preparation Example 1 Preparation of a Polymer Containing a Repeating Unit Represented by Chemical Formula 1a

18.0 g (0.1 mol) of 9-fluorenone was added to a three-neck 250 mL flask equipped with a reflux tube, and 1,2,3,4-tetrahydronaphthalene (1,2,3,4) was used as a solvent. 100 mL of -tetra hydronaphthalene (THN) was added, followed by 15.8 g (0.11 mol) of 1-naphtol. After raising the temperature of the reactor (flask) to 130 ° C, 3.2 g (0.03 mol) of 3-mercaptopropanol was added to the reactor, and 3.4 g of 18 N sulfuric acid was slowly added thereto. After the addition of sulfuric acid, the temperature of the reactor was maintained at 150 ° C and reacted for 18 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the pH of the reaction solution was adjusted to 7 using NaOH 2N solution, the water layer was removed, and the temperature of the reactor was raised to 90 ° C., followed by using hot water. The reaction solution was washed three times. After washing with water, the temperature of the reactant was lowered to room temperature again, and slowly added dropwise to 1 L of methanol to precipitate a polymer in powder form, which was then dried for 6 hours in a vacuum oven at 60 ° C. to include a polymer comprising a repeating unit represented by Chemical Formula 1a. 20.7 g (61% yield) were obtained. The weight average molecular weight (Mw) and polydispersity (PD) of the synthesized polymer were measured by gel permeation chromatography (GPC) (Mw = 2,860, PD = 3.21).

Preparation Example 2 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1b

Production Example 1, except that 17.6 g (0.11 mol) of 1,5-dihydroxynaphthalene was used instead of 15.8 g (0.11 mol) of 1-naphtol. In the same manner as in the polymer 24.2g containing a repeating unit represented by the formula (1b) was obtained (yield: 61%, Mw = 3,420, PD = 3.61).

Preparation Example 3 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1c

Production Example 1, except that 17.6 g (0.11 mol) of 1,6-dihydroxynaphthalene was used instead of 15.8 g (0.11 mol) of 1-naphtol. 25.7 g of a polymer including a repeating unit represented by Chemical Formula 1c was obtained in the same manner as in (Yield: 72%, Mw = 3,110, PD = 4.26).

Preparation Example 4 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1d

Production Example 1, except that 17.6 g (0.11 mol) of 2,6-dihydroxynaphthalene was used instead of 15.8 g (0.11 mol) of 1-naphtol. In the same manner as in the polymer 24.9g containing a repeating unit represented by the formula (1d) was obtained (yield: 70%, Mw = 4,280, PD = 5.11).

Preparation Example 5 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1e

In the same manner as in Preparation Example 1, except that 21.3 g (0.11 mol) of 9-hydroxyanthracene was used instead of 15.8 g (0.11 mol) of 1-naphtol. 17.7 g of a polymer including a repeating unit represented by Chemical Formula 1e was obtained (yield: 45%, Mw = 1,990, PD = 2.26).

Preparation Example 6 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1f

In the same manner as in Preparation Example 1, except that 21.3 g (0.11 mol) of 9-phenanthrenol was used instead of 15.8 g (0.11 mol) of 1-naphtol. 18.9 g of a polymer including a repeating unit represented by Chemical Formula 1f was obtained (yield: 48%, Mw = 2,150, PD = 2.83).

Preparation Example 7 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1g

Instead of 15.8 g (0.11 mol) of 1-naphtol, except that 24.8 g (0.11 mol) of 1,8,9-trihydroxynaphthalene was used. In the same manner as in Preparation Example 1, 26.2g of a polymer including a repeating unit represented by Chemical Formula 1g was obtained (yield: 61%, Mw = 4,650, PD = 4.54).

Preparation Example 8 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1h

Instead of 15.8 g (0.11 mol) of 1-naphtol, 25.6 g (0.11 mol) of 1-pyrenol was used, except that 15.6 g (0.11 mol) of 1-naphtol was used. 16.8 g of a polymer including a repeating unit represented by 1 h was obtained (yield: 38%, Mw = 1,610, PD = 2.18).

Preparation Example 9 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1i

Instead of 15.8 g (0.11 mol) of 1-naphtol, 31.4 g (0.11 mol) of 1,1'-bi-2-naphthalenol was used. Except that, 27.2 g of a polymer including a repeating unit represented by Chemical Formula 1i was obtained by the same method as in Preparation Example 1 (yield: 55%, Mw = 2,480, PD = 2.86).

Preparation Example 10 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1j

Instead of 18.0 g (0.1 mol) of 9-fluorenone, 23.0 g (0.1 mol) of benzo [b] fluoren-11-one is used, Production Example 1, except that 17.6 g (0.11 mol) of 1,6-dihydroxynaphthalene was used instead of 15.8 g (0.11 mol) of 1-naphtol. 21.5 g of a polymer including a repeating unit represented by Chemical Formula 1j was obtained in the same manner as in (Yield: 53%, Mw = 2,650, PD = 3.42).

Preparation Example 11 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1k

Instead of 18.0 g (0.1 mol) of 9-fluorenone, 28.0 g (0.1 mol) of dibenzo [b, h] fluoren-12-one ) And 17.6 g (0.11 mol) of 1,6-dihydroxynaphthalene instead of 15.8 g (0.11 mol) of 1-naphtol. In the same manner as in Preparation Example 1, 23.7 g of a polymer including a repeating unit represented by Chemical Formula 1k was obtained (yield: 52%, Mw = 1,810, PD = 4.88).

Preparation Example 12 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1l

Instead of 18.0 g (0.1 mol) of 9-fluorenone, 19.4 g (0.1 mol) of 10H-anthracen-9-one was used, and the 1-naphthol ( Instead of 15.8 g (0.11 mol) of 1-naphtol), 17.6 g (0.11 mol) of 1,6-dihydroxynaphthalene was used, except that 17.6 g (0.11 mol) of 1-naphtol was used. 23.0 g of a polymer including a repeating unit represented by Chemical Formula 1l was obtained (yield: 62%, Mw = 3,860, PD = 2.65).

Preparation Example 13 Preparation of Polymer Containing Repeating Unit Represented by Chemical Formula 1m

Instead of 18.0 g (0.1 mol) of 9-fluorenone, 29.4 g (0.1 mol) of 13H-pentacen-6-one was used and the 1-naphthol was used. In the same manner as in Preparation Example 1, except that 17.6 g (0.11 mol) of 1,6-dihydroxynaphthalene was used instead of 15.8 g (0.11 mol) of (1-naphtol). 19.8 g of a polymer including a repeating unit represented by Chemical Formula 1m was obtained (yield: 42%, Mw = 2,940, PD = 2.91).

Preparation Example 14 Preparation of Polymer Containing Repeating Unit Represented by Formula (5)

Into a 250 ml flask with nitrogen reflux, 100 g of bisphenol fluorine was added, 35 ml of 37% aqueous formaldehyde solution and 3 g of anhydrous oxalic acid were added, and then the temperature of the reactor (flask) was adjusted. Raised to 100 ℃ proceeded for 20 hours. After completion of the reaction, all products were dissolved using 300 ml of methyl isobutyl ketone (MIBK) and washed with deionized water to remove the acid catalyst (oxalic acid). After the acid catalyst was removed, methyl isobutyl ketone was removed under reduced pressure, and the product was dried to obtain 62 g of a polymer including a repeating unit represented by the following Formula (5). The weight average molecular weight (Mw) and polydispersity (PD) of the synthesized polymer were measured using gel permeation chromatography (GPC) based on polystyrene (Mw = 7,410, PD = 4.53). ).

[Formula 5]

[Experimental Examples 1-1 to 1-13 and Reference Examples 1-1 to 1-2] Measurement of Thermal Stability of Polymers

A polymer containing the aromatic ring-containing polymer prepared in Preparation Examples 1 to 13 and the repeating unit represented by Formula 5 prepared in Preparation Example 14 and a conventional novolak resin, for example, a repeat represented by Formula 6 below. In order to measure the thermal stability of a polymer comprising units (where m is an integer from 0 to 3, Mw = 7,410, PD = 4.53, meta / para reaction rate (m: p = 6: 4)), a thermogravimetric analyzer ( The mass loss amount (% by weight) at 400 ° C. was measured by a thermo gravimetric analyzer (TGA, manufacturer: TA). The results are shown in Table 1 below.

[Formula 6]

Table 1

	Polymer	Heating temperature (℃)	Mass loss (wt%)
Experimental Example 1-1	Formula 1a	400	4.1
Experimental Example 1-2	Formula 1b	400	4.8
Experimental Example 1-3	Formula 1c	400	4.5
Experimental Example 1-4	Formula 1d	400	3.8
Experimental Example 1-5	Formula 1e	400	3.6
Experimental Example 1-6	Formula 1f	400	4.2
Experimental Example 1-7	Formula 1g	400	4.6
Experimental Example 1-8	Formula 1h	400	3.9
Experimental Example 1-9	Formula 1i	400	3.1
Experimental Example 1-10	Formula 1j	400	2.4
Experimental Example 1-11	Chemical Formula 1k	400	2.6
Experimental Example 1-12	Formula 1l	400	3.8
Experimental Example 1-13	Formula 1m	400	2.8
Reference Example 1-1	Formula 5	400	19.8
Reference Example 1-2	Formula 6	400	71.2

[Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-17] Preparation of resist underlayer film composition

In order to prepare a resist underlayer film composition, a polymer synthesized in Preparation Examples 1 to 14 (a polymer including a repeating unit represented by Formula 1a to 1m and Formula 5), a polymer including a repeating unit represented by Formula 6, A compound represented by 4 (a leveling agent, MER-series from Meiwa, Japan) and a crosslinking agent (tetramethoxymethyl glycoluril, trade name: MX-270) were used as components and contents shown in Table 2 below. In each composition, 0.1 g of pyridinium para-toluenesulfonate and 0.04 g of a surfactant (manufacturer: DIC Corporation, product name: R-08) were mixed as a catalyst, and each component was propylene glycol mono. Dissolved in a mixed solvent of 60 g of propyleneglycol monomethylether acetate (PGMEA) and 29 g of cyclohexanone (CH), and then filtered through a microfilter having a diameter of 0.45 µm for use in a lithography process with a multilayer film resist composition. A resist underlayer film composition was prepared.

TABLE 2

division	Polymer resin		Leveling agent		Crosslinking agent
	Polymer	usage	additive	usage
Comparative Example 1-3	Formula 1a	10 g	-	-	MX-270 / 1g
Comparative Example 1-4	Formula 1b	10 g	-	-	MX-270 / 1g
Comparative Example 1-5	Formula 1c	10 g	-	-	MX-270 / 1g
Comparative Example 1-6	Formula 1d	10 g	-	-	MX-270 / 1g
Comparative Example 1-7	Formula 1e	10 g	-	-	MX-270 / 1g
Comparative Example 1-8	Formula 1f	10 g	-	-	MX-270 / 1g
Comparative Example 1-9	Formula 1g	10 g	-	-	MX-270 / 1g
Comparative Example 1-10	Formula 1h	10 g	-	-	MX-270 / 1g
Comparative Example 1-11	Formula 1i	10 g	-	-	MX-270 / 1g
Comparative Example 1-12	Formula 1j	10 g	-	-	MX-270 / 1g
Comparative Example 1-13	Chemical Formula 1k	10 g	-	-	MX-270 / 1g
Comparative Example 1-14	Formula 1l	10 g	-	-	MX-270 / 1g
Comparative Example 1-15	Formula 1m	10 g	-	-	MX-270 / 1g
Comparative Example 1-16	Formula 1a	10 g	-	-	-
Comparative Example 1-17	Formula 1h	10 g	-	-	-
Example 1-1	Formula 1a	6.5g	MER-7940S	3.5 g
Example 1-2	Formula 1a	6.5g	MER-7940F	3.5 g	-
Example 1-3	Formula 1a	6.5g	MER-7950S	3.5 g	-
Example 1-4	Formula 1a	6.5g	MER-7959S	3.5 g	-
Example 1-5	Formula 1a	6.5g	MER-7966	3.5 g	-
Example 1-6	Formula 1a	6.5g	MER-7968	3.5 g	-
Example 1-7	Formula 1a	6.5g	MER-7981S	3.5 g	-
Example 1-8	Formula 1a	5.0 g	MER-7966	5.0 g	-
Example 1-9	Formula 1a	3.5 g	MER-7966	6.5g	-
Comparative Example 1-1	Formula 5	10 g	-	-	MX-270 / 1g
Comparative Example 1-2	Formula 6	10 g	-	-	MX-270 / 1g

[Examples 2-1 to 2-9 and Comparative Examples 2-1 to 2-17] Preparation and Evaluation of Optical Properties of Resist Underlayer Film

Each of the resist underlayer film compositions prepared in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-17 was applied onto a silicon wafer using a spin coater, respectively, and then 240 using a hot plate. It heated at 1 degreeC for 1 minute, and produced the resist underlayer film of 200 nm thickness. The refractive index (n value) and optical absorption coefficient (k value) at wavelength 248 nm and wavelength 193 nm of the prepared resist underlayer film were measured using a spectroscopic ellipsometer (manufacturer: Ulam), and the results are shown in Table 3. It was. In addition, the wafer is ethyl lactate (EL), propylene glycol monomethylether (PGME), propylene glycol monomethylether acetate (PGMEA) and cyclohexanone (CH) ) Was immersed for 1 minute, and the thickness of the immersed wafer was measured. As a result, all the resist underlayer films did not dissolve in the general semiconductor solvent and showed no change in thickness.

TABLE 3

division	Refractive index n (at 248 nm)	Optical absorption coefficient K (at 248 nm)	Refractive index n (at 193 nm)	Optical Absorption Coefficient K (at 193 nm)
Comparative Example 2-3	1.80	0.76	1.40	0.53
Comparative Example 2-4	1.86	0.78	1.41	0.49
Comparative Example 2-5	1.91	0.78	1.44	0.51
Comparative Example 2-6	1.89	0.76	1.38	0.53
Comparative Example 2-7	1.95	0.72	1.41	0.42
Comparative Example 2-8	1.88	0.79	1.44	0.40
Comparative Example 2-9	1.97	0.73	1.39	0.44
Comparative Example 2-10	1.98	0.81	1.35	0.37
Comparative Example 2-11	1.91	0.81	1.39	0.52
Comparative Example 2-12	1.94	0.76	1.41	0.54
Comparative Example 2-13	1.97	0.78	1.41	0.53
Comparative Example 2-14	1.86	0.77	1.45	0.60
Comparative Example 2-15	1.97	0.72	1.39	0.51
Comparative Example 2-16	1.78	0.78	1.38	0.51
Comparative Example 2-17	1.95	0.79	1.36	0.40
Example 2-1	1.78	0.73	1.44	0.56
Example 2-2	1.80	0.78	1.36	0.54
Example 2-3	1.81	0.81	1.42	0.54
Example 2-4	1.75	0.78	1.42	0.55
Example 2-5	1.84	0.78	1.40	0.51
Example 2-6	1.79	0.75	1.44	0.61
Example 2-7	1.79	0.79	1.39	0.58
Example 2-8	1.84	0.82	1.45	0.54
Example 2-9	1.80	0.82	1.41	0.55
Comparative Example 2-1	1.96	0.82	1.54	0.70
Comparative Example 2-2	1.98	0.87	1.62	0.81

[Examples 3-1 to 3-9 and Comparative Examples 3-1 to 3-17] Preparation of the resist underlayer film and evaluation of the etching rate

In order to measure the dry etching rate (etch rate using CF ₄ / CHF ₃ -based gas) of the resist underlayer film, each of the resists prepared in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-17 After applying the underlayer film composition on the silicon wafer to a thickness of 300 nm, each underlayer film was heated at a temperature of 240 ° C. and 400 ° C. for 1 minute to form a resist underlayer film. The wafer on which the resist underlayer film was formed was etched under CF ₄ / CHF ₃ gas conditions using an etching apparatus (product name: TCP9400SE, manufacturer: Lam Research). The etching rate (kV / sec) was measured using the difference in thickness before and after etching of the resist underlayer film, and the result is shown in Table 4.

Table 4

division	bake temperature (degrees, ℃)	Etch Rate (µs / sec)	bake temperature (degrees, ℃)	Etch Rate (µs / sec)
Comparative Example 3-3	240	88	400	85
Comparative Example 3-4	240	78	400	77
Comparative Example 3-5	240	86	400	89
Comparative Example 3-6	240	81	400	80
Comparative Example 3-7	240	80	400	80
Comparative Example 3-8	240	78	400	76
Comparative Example 3-9	240	76	400	74
Comparative Example 3-10	240	87	400	82
Comparative Example 3-11	240	74	400	76
Comparative Example 3-12	240	84	400	84
Comparative Example 3-13	240	75	400	76
Comparative Example 3-14	240	91	400	82
Comparative Example 3-15	240	86	400	88
Comparative Example 3-16	240	77	400	76
Comparative Example 3-17	240	79	400	74
Example 3-1	240	92	400	87
Example 3-2	240	89	400	86
Example 3-3	240	94	400	89
Example 3-4	240	92	400	88
Example 3-5	240	90	400	87
Example 3-6	240	91	400	85
Example 3-7	240	85	400	83
Example 3-8	240	86	400	82
Example 3-9	240	88	400	82
Comparative Example 3-1	240	112	400	106
Comparative Example 3-2	240	123	400	-

[Examples 4-1 to 4-9 and Comparative Examples 4-1 to 4-17] Preparation of resist underlayer film and evaluation of gap fill characteristics

Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1 on a wafer having a line width of 150 nm and 60 nm and a pattern having a height of 220 nm, respectively. Each resist underlayer film composition prepared at −17 was applied to a thickness of 250 nm using a spin coater, and then heated at 400 ° C. for 1 minute using a hot plate to form a resist underlayer film. The cross section of the formed resist underlayer film was observed with a FE-SEM (Field Emission Scanning Electron Microscope, Hitachi, product name: S-4300) equipment. When the difference of the space part) is less than 3 nm, it was determined as "very good", "good" when 3 to 10 nm, and "bad" when it exceeds 10 nm, and the results are shown in Table 5. In addition, FE-SEM cross-sectional photographs of the resist underlayer film formed in Comparative Example 4-1 and the resist underlayer film formed in Example 4-10 are shown in FIGS. 1 and 2, respectively. As shown in Fig. 1, the resist underlayer film formed in Comparative Example 4-1 is degraded in flatness.

Table 5

division	Gap fill attribute
Comparative Example 4-3	Bad
Comparative Example 4-4	Bad
Comparative Example 4-5	Good
Comparative Example 4-6	Bad
Comparative Example 4-7	Good
Comparative Example 4-8	Bad
Comparative Example 4-9	Bad
Comparative Example 4-10	Bad
Comparative Example 4-11	Good
Comparative Example 4-12	Good
Comparative Example 4-13	Bad
Comparative Example 4-14	Good
Comparative Example 4-15	Good
Comparative Example 4-16	Bad
Comparative Example 4-17	Good
Example 4-1	Very good
Example 4-2	Very good
Example 4-3	Very good
Example 4-4	Very good
Example 4-5	Very good
Example 4-6	Very good
Example 4-7	Very good
Example 4-8	Very good
Example 4-9	Very good
Comparative Example 4-1	Bad
Comparative Example 4-2	Bad

The present invention relates to a polymer used in a resist underlayer film, and improves the thermal stability, gap fill property, optical property, and etching resistance for a hard mask role of a conventional resist underlayer film. In general, the resist underlayer film has thermal stability at 250 ° C. or lower, but does not satisfy the thermal stability required by the resist underlayer film at a high temperature of 400 ° C. or higher. However, the present invention, by using a polymer containing a repeating unit represented by the formula (1) using the carbon and carbon-to-carbon bond of the aromatic ring, not only improved the high temperature thermal stability of 400 ℃ or more, but also as formula (2) as an additive By using the displayed noblock resin or styrene derivative resin, the gap fill property and the planarization rate of the resist underlayer film during spin coating of the underlayer film composition were improved.

Claims (8)

1. An aromatic ring-containing polymer comprising a repeating unit represented by the following formula (1),

   [Formula 1]

   

   In Formula 1, R ₁ is a monocyclic or polycyclic aromatic hydrocarbon group having 5 to 20 carbon atoms, R ₂ and R ₃ are each independently a monocyclic or polycyclic aromatic hydrocarbon group having 4 to 14 carbon atoms, a is an integer from 1 to 3 and b is an integer from 0 to 2;

   A compound represented by Formula 4,

   [Formula 4]

   

   In Formula 4, n is an integer of 1 to 250; And

   A resist underlayer film composition containing an organic solvent.
2. The resist underlayer film composition of claim 1, wherein the aromatic ring-containing polymer including the repeating unit represented by Formula 1 is selected from the group consisting of a polymer including the repeating unit represented by the following Formulas 1a to 1m.

    [Formula 1a]

   

   [Formula 1b]

   

   [Formula 1c]

   

   [Formula 1d]

   

   [Formula 1e]

   

   [Formula 1f]

   

   [Formula 1g]

   

   [Formula 1h]

   

   Formula 1i]

   

   [Formula 1j]

   

   [Formula 1k]

   

   [Formula 1l]

   

   [Formula 1m]

   
3. The weight average molecular weight of the aromatic ring-containing polymer including the repeating unit represented by Formula 1 is 200 to 50,000, and the weight average molecular weight of the compound represented by Formula 4 is 200 to 30,000. Resist Underlayer Film Composition.
4. The method of claim 1, wherein the organic solvent is propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CH), ethyl lactate (EL), gamma butyrolactone (GBL) And a mixture thereof. A resist underlayer film composition.
5. According to claim 1, wherein the content of the aromatic ring-containing polymer comprising a repeating unit represented by the formula (1) is 1 to 25% by weight, the content of the compound represented by the formula (4), the repeating unit represented by the formula (1) It is 30 to 150 parts by weight based on 100 parts by weight of the aromatic ring-containing polymer containing, the remainder is an organic solvent resist.
6. Aromatic ring-containing polymer, including a repeating unit represented by the following formula (1) on the substrate to be etched,

   [Formula 1]

   

   In Formula 1, R ₁ is a monocyclic or polycyclic aromatic hydrocarbon group having 5 to 20 carbon atoms, R ₂ and R ₃ are each independently a monocyclic or polycyclic aromatic hydrocarbon group having 4 to 14 carbon atoms, a is an integer from 1 to 3 and b is an integer from 0 to 2; A compound represented by Formula 4,

   [Formula 4]

   

   In Formula 4, n is an integer of 1 to 250; And forming a resist underlayer film using the resist underlayer film composition comprising an organic solvent,

   Forming a photoresist layer on the resist underlayer film;

   Generating a pattern of radiation-exposed regions of the photoresist layer by exposing the photoresist layer to radiation in a predetermined pattern;

   Selectively removing the photoresist layer and the resist underlayer film along the pattern to expose the substrate in the form of the pattern; And

   Etching the exposed portion of the substrate.
7. The method of claim 6, wherein the forming of the resist underlayer film comprises spin-coating the resist underlayer film composition on a substrate with a thickness of 40 to 600 nm, and heating the film at a temperature of 240 to 400 ° C. for 50 to 180 seconds. And the thickness of the formed resist underlayer film is 40 to 550 nm.
8. The method of claim 6, wherein the resist underlayer film is removed by dry etching using a CHF ₃ / CF ₄ mixed gas.

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